1. Field of the Invention
The present invention relates to percutaneous catheterization systems, and more particularly to a device for and method of irrigating catheterization systems.
2. Description of Related Art
Intravenous ("IV") catheters are commonly used in the treatment of patients to introduce fluids directly into the bloodstream of the patient. In IV catheterization, a supply of fluid, maintained in a container, is typically located above the patient. A catheter supply tube carries the fluid from the container to a catheter attached to patient, thus introducing the fluid into the patient. The catheter is typically inserted in a vein located on the lateral side of the patient's hand or a vein located on the medial side of the arm. The catheter, however, may alternatively be introduced into another body lumen, such as, for example, an artery or an organ.
Typically, a nurse introduces a needle or other stylet through the cannula portion of the catheter and into the skin of the patient at a desired location. The nurse subsequently removes the needle after the cannula is inserted into the body lumen. Fluid flows directly into the lumen (e.g., vessel) of the patient with the fluid supply tube placing the catheter in fluidic communication with the fluid supply container. Gravity and the pressure generated by the head of the fluid above the patient produces fluid flow into the body lumen.
Flow through the catheter, however, may cease because the head of the liquid above the patient is insufficient to force the fluid into the vessel of the patient, as typically is the case when the fluid supply container has fully drained. Flow may also cease when a nurse or like healthcare provider clamps off the flow to administer medication through a "Y"-site port commonly located on the distal side of the clamp. As used herein, "proximal" and "distal" are used in reference to the proximity of the fluid supply container.
When the IV flow stops, blood clots may form and/or other organic debris may deposit on the distal end of the catheter cannula, thus clogging the catheter. Blood clotting occurs within 2 to 3 minutes after the IV flow ceases, and the clot increases in size thereafter.
Because the catheter commonly remains in place during the catheterization period, which typically is maintained for at least several days (depending upon the condition of the patient), the nurse must unclog the catheter by irrigation. That is, the nurse forces fluid through the catheter under sufficient pressure to displace the blockage (i.e., the blood clot or organic debris).
Nurses commonly irrigate the catheterization site using a syringe. The nurse first fills the syringe with liquid from the IV line and then clamps off a section of the fluid supply tube filled with liquid proximate to the indwelling catheter. The nurse inserts the needle of the syringe into the line communicating with the catheter and injects the fluid into the line to increase the fluidic pressure within the catheter to a level greater than that required to dislodge the blockage.
Although this method may be effective, it suffers from several drawbacks. The method exposes the nurse or like healthcare provider to contaminated medical sharps which raises the possibility of the sharp (e.g., the needle of the syringe) sticking the nurse. On average, this exposure occurs at least twice a day. If the syringe needle does stick (or prick) the nurse, he or she as must undergo a series of inoculations, as well as undergo a series of test together with the patient to determine among other things whether the patient is HIV (Human Immunodeficiency Virus) positive. Such inoculations and tests pose substantial expense to hospitals and clinics.
Moreover, the nurse must retrieve a syringe after noticing that the IV flow has stopped. As mentioned above, blood clots within 2 to 3 minutes and the clot increases in size each minute thereafter. Thus, during the time the nurse retrieves the syringe, the blood clot grows, becoming more difficult to dislodge. In addition, the time expended retrieving the syringe adds to administrative costs, thus increasing the cost of healthcare.
This irrigation procedure also causes substantial discomfort to the patient. Nurses typically use large syringes (e.g. 3 to 12 cubic centimeters) to irrigate the catheterization site which raises the pressure within the catheter above the pressure required to dislodge the blockage. A substantial amount of fluid thus flows into the body lumen when the block dislodges, causing the vessel to swell or causing damage to the lining of the vessel, which adds to the patient's discomfort. Further, this irrigation process may lead to inflammation of the vein (Phlebitis), to Thrombophlebitis, or to subcutaneous infiltration (i.e, perforation of vessel wall). The latter consequence necessitates changing of the catheter insertion site, creating further discomfort to the patient and adding administrative expense. Thus, the present irrigation method, by crudely raising the fluidic pressure beyond that which is required to dislodge the blockage, unnecessarily pains the patient and often damages the catheterized vessel.